/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/GeometrySelector.h
Locking support. When a Selector is locked, it will not allow selection changes. The primary use of this is to support configurable enable/disable of selection on certain types of objects (eg on static meshes). Although it could potentially be supported at a higher level, this adds a lot of complications to state management that are avoided if the Selector is always created.
virtual bool IsLockable() const